How to focus on the files?

[brainslug]

Perhaps like some others on this site, I first encountered hypnosis via Isabella Valentine. While listening to these files I got into the habit of repeating her voice in my mind, as though to confirm it to myself. But I have yet to have any profound success with any file except for one by Saranoga and I do not really even remember my thoughts while listening to it; they seemed to simply melt into the file.

Supposing that this is what is supposed to happen, how should I start off listening to a file? Obviously you cannot instant trance upon listening to a file(without being traced by a file first at least) so how should I start listening to the file? By Just passively hearing but really focusing? By actively trying to think of what is going on? By repeating the words in my head?